Movement dampers are used in various assemblies to control the movement of assembly components. For example, in furniture and cabinetry it is known to use dampers for controlling movement of a drawer or door in at least one direction. In automobiles, it is known to use dampers on glovebox and console doors, and the like.
Many such drawers, doors and components are provided with automatic closure mechanism that utilize spring assists for moving the component in one direction, typically in the closing direction. With spring assists, the component can be made self-closing, requiring only an initial start to unseat it from a secured, opened position. Although spring or other assists are beneficial in reducing the effort required for closing, and for ensuring that the component closes completely, an assist of sufficient strength to close automatically a heavily loaded drawer or the like can result in abrupt movements and rapid closing, with significant impact upon reaching the fully closed position. Therefore, it is advantageous to temper, or damp the action of the spring, so that the drawer, door or the like closes more gently.
Since the opening motion of a door or drawer may be done without mechanical assist, and in fact may itself be restrained by the expansion of an extension spring used to assist closing, further damping is not needed and may be undesirable. Therefore, often it is desirable to deactivate or circumvent the damping mechanism during operation in one direction, such as when a drawer is being pulled open. A damper that is operated in one direction is referred to commonly as a “one-way” damper, and a damper operated in both directions commonly is referred to as a “two-way” damper.
It is known to use a damper to provide rotational resistance of a gear on a mechanism such as an automatic closer through driving engagement between the gear of the mechanism and a gear of the damper. Resistance to rotation of the gear on the damper, which is inherent in the structure of the damper, is thereby imparted to rotation of the mechanism gear. Such damping devices frequently are referred to as gear dampers.
Some gear dampers are operated as one-way dampers through the selective engagement or disengagement of the cooperating gears. However, structure necessary to engage and disengage the gears selectively adds complexity to the device, and can be a source of potential failure.
Alternatively, the damper itself can be provided with a clutch. The clutch allows the gear of the damper to be fully engaged with a damping portion of a rotor in the damper when the gear is rotated in one direction, and to be effectively disengaged from the rotor, and therefore freewheeling, when the gear is rotated in the opposite direction. Known dampers of this type have used internal clutch springs, requiring the use of two-piece rotors. A two-piece rotor can introduce an undesirably large degree of play or looseness in the device, and can become a point of additional component wear, and potential failure. Internal leakage of the damping fluid, typically a viscous fluid, can contaminate an internal clutch spring, rendering the clutch nonfunctioning.
Therefore, it is desirable to provide a one-way damper having a one-piece rotor, and a clutch that is less susceptible to failure than are known damper clutch structures.
What is needed in the art is a damper that is easier to assemble, and more reliable in operation than are known designs.